Over the past 10-20 years research has focused on increasing jet engine performance while reducing engine weight and reducing the costs associated with engine production and maintenance. In particular, government and military funded programs have focused on using ceramic components for the hot section of gas turbine engines to allow for higher turbine inlet temperatures and, therefore, higher thermal efficiencies. In addition, research is focusing on a truly integrated engine and airframe propulsion system in which the engine casing becomes a part of the airframe. This would allow for a dramatic weight reduction in overall weight and an increase in engine performance. However, these development programs have focused on 70 year old gas turbine technology.
In addition, the DOD and Armed Services are now demanding significant increases in electric output from turbine flight engines. For example, there are now requirements for the generation of up to 2-5 megawatts of electrical power that is needed to power on-board directed energy weapons and all electric aircraft subsystems. Currently, US Air Force requirements for future unmanned and manned systems are demanding propulsion capabilities which can sustain supersonic speeds as in Mach 1.5-3.5 across a complete flight regime, lift-off to landing, and deliver high power energy weapons with all electric sub-systems for aircraft function. Future aircraft concepts are demanding in excess of 1.0 megawatt of power which current turbine engine companies cannot deliver off of their present engine designs, largely because they are restricted by the reduction performance of gear boxes, drive shafts and the generator added on as an additional component which is not made by the OEM engine supplier.
In traditional gas turbine engines, the combustor/propulsor, dynamic components are designed to be in tension with heavy axial drive shafts (or spools), and gear boxes. These systems are quite heavy and typically limit the thrust to weight ratios to not more than 7 to 1.
Accordingly, a need exists for an engine design that is able to provide very high thrust to weight ratios, has optimized aerodynamic flight conditions across the entire flight envelope and can generate substantial surplus electrical power output.
A further need exists for a turbine engine design without a drive shaft (and its volume and weight constraints) that has optimize aerodynamic efficiency along with lightweight high temperature materials.
Yet another exists for new engine turbomachinary that utilizes new high power electromagnetics to electrically segment the bypass fan from the compressor and the turbine.